Check for Crawling Errors: This can be one of the most frequent errors for well established sites. Glitches like sitemap publishing and server downtimes can maintain the spiders from crawling your latest content when it is published. Though it seems like a small error, it can be fatal, especially if you're news based where the latest updates are the most significant. Keep your eye on this by watching Google's Webmaster's tool and crawling frequency details.

Check Your Google Site Index Number Fluctuations: Any glitches in Google will almost immediately be reflected in the site index. Glitches like duplicate page issues or other penalties will come into sight as a reduction in the pages shown as indexed by Google. Keep a constant eye on the total number of pages indexed by Google for a good sign of the general health of your site. If you see heavy fluctuations in your site's index, you have got a problem.

Check for Competition Changes on SERPs: The reason why you must be doing SEO housekeeping is because your contest already does. They will be doing anything they possibly can, experimenting and making tweaks to get to the top. Keep an eye on your contest, specially the companies that make use of SEO and are willing to try something new.

Check for Broken Links: There are lots of links that connect a site. It is natural for one or two to come undone from time to time. Similar to the plumbing in your house, they constantly need checked for leaks and breakdowns. The only way to sustain on them is to constantly check all your links at regular intervals to ensure they are up and running smoothly. A broken link can isolate key pages on your site, strictly impacting its SEO health.